1. Field of the Invention
The present invention relates to an image forming apparatus, a storage medium and an image forming method.
2. Description of the Related Art
An image forming apparatus (of electrophotographic printing system), which performs image formation by using an electrophotographic process, generally forms (prints) an image on a sheet of paper or the like by using electrostatic elements and operations, such as charges and electrostatic attraction at the time of image formation.
Consequently, if the situations of the internal temperature and humidity of the image forming apparatus change, the process conditions of the electrophotographic process (especially process conditions of a transfer process) are influenced by the changes to vary. As a result, the image quality of an image printed on a sheet of paper sometimes does not become desired one.
In order to solve such a problem, the technique of detecting the internal temperature and humidity of an image forming apparatus to correct the process conditions of an electrophotographic process on the basis of the detected values was disclosed (see Japanese Patent Application Laid-Open Publications No. H 11-167243 and No. 2000-98771).
Furthermore, the technique of detecting not only the inside of an image forming apparatus but also the external environment state to correct the process conditions of an electrophotographic process on the basis of these detected values was also disclosed (see Japanese Patent Application Laid-Open Publication No. 2007-156201).
Furthermore, the technique referring to the history of the internal environment (temperature and humidity) of an image forming apparatus to always perform correction was also disclosed (see Japanese Patent Application Laid-Open Publication No. 2001-296759).
The environment (temperature and humidity) in an image forming apparatus is, however, in the process of changing during an operation of an image forming apparatus. Even if the correction of the process conditions of an electrophotographic process is performed in such a situation on the basis of the detected environment conditions (temperature, humidity) and history by using the techniques disclosed in Japanese Patent Application Laid-Open Publications No. H 11-167243, No. 2000-98771, No. 2007-156201 and No. 2001-296759, the corrected process conditions do not become proper ones. Consequently, the image quality of an image printed on a sheet of paper does not become a desired one.